Shelah's excellence conjecture for atomic classes

Let $T$ be a countable first-order theory and let $K_T$ be its class of atomic models. Excellence conjecture. If $K_T$ is categorical in every $\beth_n$ for $n<\beth_0$, then $K_T$ is excellent. The claim would show that the counterexamples discussed in the source are best possible; the source says this appears far away and treats it as open.